ext2fs: update format specifiers for ext4 type.

Reported by:	Sam Fourman Jr.
MFC after:	3 weeks
Some small cleanups to the fixes in r180340:
- Set NOTE_TRACKERR before running filt_proc().  If the knote did not
  have NOTE_FORK set in fflags when registered, then the TRACKERR event
  could miss being posted.
- Don't pass the pid in to filt_proc() for NOTE_FORK events.  The special
  handling for pids is done knote_fork() directly and no longer in
  filt_proc().

MFC after:	2 weeks
init: Set kernel login class and CPU mask on new processes.

In particular, this makes the kernel login class on processes started from
/etc/rc "daemon" instead of "default".

Reviewed by:	trasz
db: Use O_CLOEXEC instead of separate fcntl() call.